Image processing apparatus

ABSTRACT

An image processing apparatus includes an interface through which scanned image data obtained by scanning a designated region, is acquired, and a processor. The processor extracts a contour line representing a document area from the scanned image data, extracts vertices of the contour line, determines whether a plurality of original documents is present in the document area based on the vertices, extracts document image data of each original document from the scanned image data, and generates one file including the extracted document image data for each original document.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/895,069, filed on Feb. 13, 2018, which is based upon and claims thebenefit of priority from Japanese Patent Application No. 2017-148905,filed Aug. 1, 2017, the entire contents of each of which areincorporated herein by reference.

FILED

Embodiments described herein relate generally to an image processingapparatus.

BACKGROUND

There is an image processing apparatus which scans a plurality oforiginal documents at once and cuts out an image of each originaldocument from the scanned image. The technology is known asmulti-cropping processing. If the original documents overlap, the imageprocessing apparatus cannot separate the overlapping original documentsin some cases.

For this reason, conventionally, there is a problem in that the imageprocessing apparatus cuts out plural overlapping original documents asone original document.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an image processing apparatus according toa first embodiment;

FIG. 2 is a diagram of a scanned image;

FIG. 3 is a diagram of a contour line;

FIG. 4 is a diagram of vertices;

FIG. 5 is a diagram of a rectangle set by the image processing apparatusaccording to the first embodiment;

FIG. 6 is a diagram of the rectangle set by the image processingapparatus according to the first embodiment;

FIG. 7 is a diagram of an area of a document image;

FIG. 8 is a flowchart of the operation of the image processing apparatusaccording to the first embodiment;

FIG. 9 is a flowchart of the operation of the image processing apparatusaccording to the first embodiment;

FIG. 10 is a diagram of a scanned image that is processed according to asecond embodiment;

FIG. 11 is a diagram of a contour line that is determined according tothe second embodiment;

FIG. 12 is a diagram of vertices that are determined according to thesecond embodiment;

FIG. 13 is a diagram of first and second vertices extracted by an imageprocessing apparatus according to the second embodiment;

FIG. 14 is a diagram of a third vertex extracted by the image processingapparatus according to the second embodiment;

FIG. 15 is a diagram of a rectangle set by the image processingapparatus according to the second embodiment;

FIG. 16 is a diagram of a candidate rectangle set by the imageprocessing apparatus according to the second embodiment;

FIG. 17 is a diagram of the candidate rectangle set by the imageprocessing apparatus according to the second embodiment;

FIG. 18 is a diagram of an area of a document image;

FIG. 19 is a diagram of the display of a display in the secondembodiment;

FIG. 20 is a flowchart of the operation of the image processingapparatus according to the second embodiment;

FIG. 21 is a flowchart of the operation of the image processingapparatus according to the second embodiment; and

FIG. 22 is a flowchart of the operation of the image processingapparatus according to the second embodiment.

DETAILED DESCRIPTION

In accordance with an embodiment, an image processing apparatuscomprises an interface through which scanned image data obtained byscanning a designated region, is acquired, and a processor. Theprocessor extracts a contour line representing a document area from thescanned image data, extracts vertices of the contour line, determineswhether a plurality of original documents is present in the documentarea based on the vertices, extracts document image data of eachoriginal document from the scanned image data, and generates one fileincluding the extracted document image data for each original document.

Hereinafter, embodiments are described with reference to theaccompanying drawings.

First Embodiment

First, the first embodiment is described.

An image processing apparatus according to the embodiment scans aplurality of original documents at once. The image processing apparatusexecutes a multi-cropping process for cutting out an image of eachoriginal document from the scanned images. The image processingapparatus generates one file from the images of a plurality of theoriginal documents arranged in an overlapped manner after themulti-cropping processing is executed. The image processing apparatusmay store the file in a medium. The image processing apparatus may sendthe file to an external device.

FIG. 1 is a block diagram of an image processing apparatus 10 accordingto the embodiment.

As shown in FIG. 1, the image processing apparatus 10 includes aprocessor 11, a ROM (read-only memory) 12, a RAM (random access memory)13, a NVM (non-volatile memory) 14, a communication interface 15, ascanner interface 16, a scanner 17, an operation panel interface 18, anoperation panel 19, a display interface 20 and a display 21 as basichardware components.

The processor 11, the ROM 12, the RAM 13, the NVM 14, the communicationinterface 15, the scanner interface 16, the scanner 17, the operationpanel interface 18 and the display interface 20 are connected to oneanother via a data bus or the like.

The scanner interface 16 and the scanner 17 are connected to each othervia a data bus or the like. The operation panel interface 18 and theoperation panel 19 are connected to each other via a data bus or thelike. The display interface 20 and the display 21 are connected to eachother via a data bus or the like.

The image processing apparatus 10 may have more or less hardwarecomponents than as shown in FIG. 1.

The processor 11 controls the operation of the image processingapparatus 10. The processor 11 may include an internal memory andvarious interfaces. The processor 11 executes various programs stored inthe internal memory, the ROM 12 or the NVM 14.

Various functions realized by execution of the programs by the processor11 may alternatively be implemented in a hardware circuit. In this case,the processor 11 controls the functions implemented in the hardwarecircuit.

The ROM 12 is a nonvolatile memory in which control programs, controldata and the like are stored. The control program and the control dataare stored in the ROM 12 in advance according to the specification ofthe image processing apparatus 10. The ROM 12 stores, for example, aprogram for controlling a circuit board of the image processingapparatus 10.

The RAM 13 is a volatile memory. The RAM 13 temporarily stores databeing processed by the processor 11. The RAM 13 stores variousapplication programs based on an instruction from the processor 11. TheRAM 13 may store data necessary for executing the application program,an execution result of the application program, and the like.

The NVM 14 is a nonvolatile memory capable of writing and rewritingdata. The NVM 14 may be a hard disk, a SSD, an EEPROM®, a flash memory,or the like. The NVM 14 stores the programs, the applications, andvarious data that are used in operating the image processing apparatus10.

The communication interface 15 is used for transmitting and receivingdata to and from an external device. For example, the communicationinterface 15 supports a LAN connection or a Bluetooth® Technologyconnection.

The scanner interface 16 is used by the processor 11 to communicate withthe scanner 17. For example, the scanner interface 16 acquires thescanned image from the scanner 17. The scanner interface 16 transmitsthe acquired scanned image to the processor 11. The processor 11transmits a signal for enabling the scanner 17 to perform scanningthrough the scanner interface 16.

The scanner 17 reads an image based on a signal from the processor 11 orthe like. For example, the scanner 17 scans the original document set ona document table. In one embodiment, the scanner 17 moves a group ofsensors arranged linearly to read the original document, and moves acarriage that supplies light, which is directed to the original documentand reflected from the original document to the sensors. The scanner 17is not limited to a specific type. Also, in this example, the originaldocument is assumed to be rectangular.

The scanner 17 transmits scanned image data obtained by reading theimage to the processor 11. The scanner 17 may store the scanned imagedata in the RAM 13 or other memory.

The operation panel interface 18 is used by the processor 11 tocommunicate with the operation panel 19. For example, the processor 11receives a signal indicating an operation input to the operation panel19 through the operation panel interface 18.

Various operations are input to the operation panel 19 by a user of theimage processing apparatus 10. The operation panel 19 sends a signalindicating an operation input by the user to the processor 11. Theoperation panel 19 is, for example, a keyboard, a numeric keypad or atouch panel. The operation panel 19 may receive an input of a gesturefrom the user.

The display interface 20 is used by the processor 11 to communicate withthe display 21. For example, the processor 11 sends a signal forenabling the display 21 to display a screen through the displayinterface 20.

The display 21 is used for displaying an image output by the processor11. The display 21 is, for example, a liquid crystal monitor or thelike.

If the operation panel 19 is a touch panel, the operation panel 19 andthe display 21 may be integrated into a single unit, e.g., a controlpanel. Similarly, the operation panel interface 18 and the displayinterface 20 may also be integrated.

Next, the functions realized by the processor 11 are described. Thefollowing functions are realized by the execution of the programs storedin the NVM 14 by the processor 11.

First, the processor 11 has a function of acquiring the scanned imagedata obtained by scanning the original document.

For example, the processor 11 receives an operation to start scanningthrough the operation panel 19. Here, the user sets the originaldocument such as a business card, a card or a document on the documenttable of the scanner 17. The user places the original documents whichhe/she wishes to put in one file in an overlapped manner and sets themon the document table. The user inputs an operation to start the scan tothe operation panel 19.

If the input of the operation is received, the processor 11 transmits asignal for performing the scan to the scanner 17. The scanner 17receives the signal and scans the original document. The scanner 17transmits the scanned image data obtained by the scanner 17 to theprocessor 11, which may store the scanned image data in the RAM 13 orother memory.

FIG. 2 shows an example of the scanned image. As shown in FIG. 2, thescanned image shows original documents A to E. Here, the originaldocuments A and B overlap. The original documents C and D overlap. Theoriginal document E does not overlap with the other original documents.

The processor 11 may execute a high image quality processing such as abinarization processing on the scanned image.

The processor 11 also has a function of extracting from the scannedimage the contour line of a document area in which the original documentappears.

For example, the processor 11 extracts the contour line of the documentarea by executing an image processing such as edge detection. However,the method by which the processor 11 extracts the contour line is notlimited to any specific method.

FIG. 3 shows an example of the contour line extracted by the processor11. As shown in FIG. 3, the processor 11 extracts contour line 100,contour line 200 and contour line 300. The contour line 100 includes thecontour lines of the original documents A and B. The contour line 200includes the contour lines of the original documents C and D. Thecontour line 300 includes the contour line of the original document E.

The processor 11 has a function of extracting vertices from the contourline.

For example, the processor 11 extracts the vertices from feature valueof the image including the contour line. The processor 11 may calculatea curvature at each point of the contour line to extract the vertex. Themethod by which the processor 11 extracts the vertex is not limited to aspecific method.

FIG. 4 shows an example of the vertex extracted by the processor 11. InFIG. 4, black dots indicate the vertices. As shown in FIG. 4, theprocessor 11 extracts the vertices at corners of the original document.The processor 11 extracts the vertex at a point where edges of eachoverlapping original document intersect.

The processor 11 has a function of determining whether a plurality ofthe original documents overlaps.

The processor 11 determines whether a plurality of the originaldocuments overlaps in the contour lines. The processor 11 determineswhether the original documents overlap based on the number of thevertices of the contour lines.

If the original documents do not overlap, the processor 11 extracts fourvertices at the corners of the original document from the contour lineof the original document. If a plurality of the original documentsoverlaps, the processor 11 extracts five or more vertices as thevertices at the points where the edges of the original documentsintersect in addition to the corners of the original document areextracted.

Therefore, if the number of vertices from the contour line is five ormore, the processor 11 determines that a plurality of the originaldocuments overlaps in the contour line.

The method by which the processor 11 determines the overlap of theoriginal documents is not limited to a specific method.

Further, the processor 11 has a function of extracting first to thirdvertices adjacent to each other and forming a right angle from theextracted vertices.

The processor 11 extracts three consecutively adjacent vertices(referred to herein as first to third vertices) from the extractedvertices. The first to the third vertices are consecutive along thecontour line.

For example, the processor 11 calculates an angle between a straightline formed by the first vertex and the second vertex which areconsecutive and a straight line formed by the second vertex and thethird vertex which are consecutive. If the calculated angle is a rightangle, the processor 11 extracts the first to the third vertices as thefirst to the third vertices adjacent to each other and forming the rightangle. The processor 11 may extract the third vertex when the calculatedangle is within a predetermined angle range, e.g., from 85 degrees to 95degrees, in consideration of some margin of error.

FIG. 5 and FIG. 6 show two examples of the first to the third verticesextracted by the processor 11 from the contour line 100.

In the example shown in FIG. 5, the processor 11 extracts the vertices101 to 103. Here, an angle between a straight line formed by the vertex101 and the vertex 102 and a straight line formed by the vertex 102 andthe vertex 103 is approximately a right angle, i.e., within thepredetermined angle range of a right angle.

In the example shown in FIG. 6, the processor 11 extracts the vertices102 to 104. Here, an angle between the straight line formed by thevertex 102 and the vertex 103 and a straight line formed by the vertex103 and the vertex 104 is a right angle.

The processor 11 has a function of estimating a fourth vertex whichforms a rectangle with the extracted first to third vertices.

In other words, the processor 11 estimates the fourth vertex so that thefirst to the fourth vertices form a rectangle. For example, theprocessor 11 calculates a vector extending from the second vertex to thethird vertex. The processor 11 estimates the fourth vertex by adding avector to the first vertex.

The method by which the processor 11 estimates the fourth vertex is notlimited to a specific method.

In the example shown in FIG. 5, the processor 11 estimates a vertex 111as the fourth vertex. As shown in FIG. 5, the vertices 101 to 103 and111 form an approximate rectangle.

In the example shown in FIG. 6, the processor 11 estimates a vertex 112as the fourth vertex. As shown in FIG. 6, the vertices 102 to 104 and112 form the rectangle.

The processor 11 also has the function of determining whether therectangle formed by the first to the fourth vertices is within thedocument area defined by the contour line.

The processor 11 sets a rectangle from the first to the fourth vertices.The processor 11 then determines whether the set rectangle is containedin the contour line.

In the example shown in FIG. 5, the processor 11 sets a rectangle 121from the vertices 101 to 103 and 111. As shown in FIG. 5, the processor11 determines that the approximate rectangle 121 is not within thedocument area because it is formed outside the contour line.

In the example shown in FIG. 6, the processor 11 sets the rectangle 122from the vertex 102 to 104 and 112. As shown in FIG. 6, the processor 11determines that the rectangle 122 is within the document area.

The processor 11 stores the rectangle determined to be within thedocument area as a candidate rectangle in the RAM 13 or the NVM 14.

For example, the processor 11 stores the rectangle 122 as the candidaterectangle.

The processor 11 has a function of deleting the candidate rectanglecontained in another candidate rectangle.

The processor 11 acquires the candidate rectangle from the RAM 13 or theNVM 14. The processor 11 determines whether the candidate rectangle isincluded in another candidate rectangle. If the processor 11 determinesthat the candidate rectangle is included in another candidate rectangle,the processor 11 deletes the candidate rectangle.

The processor 11 specifies the remaining candidate rectangle notincluded in another candidate rectangle as a single document area whereone original document appears.

FIG. 7 shows an example of the single document area specified by theprocessor 11. As shown in FIG. 7, the processor 11 specifies therectangle formed by vertices 101, 107, 108 and 113 as a single documentarea 131. The processor 11 also specifies the rectangle formed by thevertices 103, 104, 105 and 114 as a single document area 132.

The processor 11 has a function of extracting the document image of eachoriginal document from the scanned image based on the single documentarea.

The processor 11 extracts the image in the single document area as thedocument image from the scanned image. In the example shown in FIG. 7,the processor 11 extracts the document image of the original document Afrom the single document area 131. The processor 11 extracts thedocument image of the original document B from the single document area132.

The processor 11 may correct an inclination of the document image. Theprocessor 11 may execute various high image quality processing on thedocument image.

The processor 11 also has a function of generating one file includingthe document image of each of the original documents arranged in theoverlapped manner.

The processor 11 collectively stores the document images of the originaldocuments arranged in the overlapped manner in one file.

For example, the processor 11 generates one multi-page file which storesone of the document images of the original documents arranged in theoverlapped manner on a first page and another of the document images ofthe original documents arranged in the overlapped manner on a secondpage. For example, the processor 11 generates a PDF file from thedocument image.

The processor 11 generates the file from the document images of theoriginal documents which are not overlapped. For example, the processor11 generates one single-page PDF file from one document image.

In the example shown in FIG. 2, the processor 11 generates one file fromthe document image of the original document A and the document image ofthe original document B. The processor 11 generates one file from thedocument image of the original document C and the document image of theoriginal document D. The processor 11 generates one file from thedocument image of the original document E.

The processor 11 may store the generated file in the NVM 14. Theprocessor 11 may store the file in a memory (such as a USB memory)inserted in the image processing apparatus 10. The processor 11 maytransmit the file to the external device through the communicationinterface 15.

Next, an example of the operation of the image processing apparatus 10is described. FIG. 8 is a flowchart of the operation of the imageprocessing apparatus 10. Here, the user sets the original document onthe scanner 17 and inputs an operation to start the scan to theoperation panel 19.

First, the processor 11 of the image processing apparatus 10 acquiresthe scanned image obtained by scanning the original document from thescanner 17 through the scanner interface 16 (ACT 11). Once the scannedimage has been acquired, the processor 11 executes the binarizationprocessing on the scanned image (ACT 12).

Once the binarization process has been executed, the processor 11extracts the contour line of the document area from the scanned image(ACT 13). Once the contour line has been extracted, the processor 11extracts the vertices from the contour line (ACT 14).

Once the vertex has been extracted, the processor 11 determines whetherthe number of vertices in one contour line is five or more (ACT 15). Ifit is determined that the number of vertices in one contour line is fiveor more (Yes in ACT 15), the processor 11 executes an image separationprocessing (which is processing described above to generate the singledocument area) (ACT 16).

If it is determined that the number of vertices in one contour line isnot five or more (No in ACT 15), or once the image separation processinghas been executed (ACT 16), the processor 11 extracts one document imagefrom the scanned image (ACT 17).

Once the document image has been extracted, the processor 11 correctsthe inclination of the document image (ACT 18). Once the inclination ofthe document image has been corrected, the processor 11 determineswhether there is another single document area (ACT 19).

If it is determined that there is another single document area (Yes inACT 19), the processor 11 returns to the processing in ACT 17.

If it is determined that there is no other single document area (No inACT 19), the processor 11 determines whether there is a plurality of thedocument images (ACT 20). If it is determined that there is a pluralityof the document images (Yes in ACT 20), the processor 11 generates amulti-page file from the plurality of the document images (ACT 21). Ifit is determined that there is not a plurality of the document images(No in ACT 20), the processor 11 generates a single page file from theoriginal document (ACT 22).

Once the multi-page file has been generated from the plurality of thedocument images (ACT 21) or the single page file has been generated fromthe original document (ACT 22), the processor 11 determines whetherthere is another contour line (ACT 23).

If it is determined that there is another contour line (Yes in ACT 23),the processor 11 returns to the processing in ACT 15. If it isdetermined that there is no other contour line (No in ACT 23), theprocessor 11 ends the operation.

Next, an example of the operation in which the processor 11 executes theimage separation processing (ACT 16) is described. FIG. 9 is a flowchartof the operation in which the processor 11 executes the image separationprocessing.

The processor 11 extracts the first to the third vertices that areadjacent to each other and form a right angle (ACT 31). Once the firstto the third vertices have been extracted, the processor 11 estimatesthe fourth vertex forming a rectangle with the first to the thirdvertices (ACT 32).

Once the fourth vertex has been estimated, the processor 11 forms therectangle from the first to the fourth vertices (ACT 33). Once therectangle has been formed, the processor 11 determines whether theformed rectangle is inside the contour line (ACT 34).

If it is determined that the formed rectangle is inside the contour line(Yes in ACT 34), the processor 11 stores the rectangle as the candidaterectangle (ACT 35).

If it is determined that the formed rectangle is not inside the contourline (No in ACT 34), or once the rectangle has been stored as thecandidate rectangle (ACT 35), the processor 11 determines whether thereare another extracted three vertices (ACT 36).

If it is determined that there are another extracted three vertices (Yesin ACT 36), the processor 11 returns to the processing in ACT 31.

If it is determined that there is no other extracted three vertices (Noin ACT 36), the processor 11 deletes the candidate rectangle containedin another candidate rectangle (ACT 37). Once the candidate rectanglecontained in another candidate rectangle has been deleted, the processor11 specifies the remaining candidate rectangle as the single documentarea (ACT 38).

If the remaining candidate rectangle is specified as the single documentarea, the processor 11 ends the operation.

The processor 11 may generate files, each of which includes a documentimage of one of the overlapping original documents.

The image processing apparatus may include a printer for printing imageson a paper. The processor 11 may control the printer to print thedocument image. If the processor 11 generates one file from a pluralityof the document images, the processor 11 may print the document imageson both sides.

The image processing apparatus as described above extracts the contourlines of a plurality of the original documents arranged in theoverlapped manner from the scanned image. The image processing apparatusspecifies the document area in which one original document appears basedon the vertexes of the contour line. Therefore, the image processingapparatus can extract the document image of each original document evenif the original documents are arranged in the overlapped manner. As aresult, the image processing apparatus can effectively execute themulti-cropping process.

The image processing apparatus generates one file from the originaldocuments arranged in the overlapped manner. Therefore, the imageprocessing apparatus can generate a multi-page file without receiving anoperation of generating the multi-page file from the user through theoperation panel.

Second Embodiment

Next, the second embodiment is described.

An image processing apparatus 1 according to the second embodimentdiffers from the image processing apparatus 1 according to the firstembodiment in that it searches for the third vertex forming the rightangle with the first and the second vertices. Therefore, for the otherpoints, the same reference numbers are given and the detaileddescription thereof is omitted.

The image processing apparatus 1 according to the second embodiment isthe same as that of the first embodiment. Therefore, the description ofthe image processing apparatus 1 according to the second embodiment isomitted.

Next, the functions carried out by the processor 11 are described. Thefollowing functions are carried out by execution of the program storedin the NVM 14 by the processor 11.

First, the processor 11 has a function of extracting adjacent first andsecond vertices from the extracted vertices.

The processor 11 extracts two vertices directly connected to each otherby the contour line as the first and the second vertices from theextracted vertices.

Here, the processor 11 acquires the scanned image in which threeoriginal documents appear.

FIG. 10 shows an example of the scanned image. As shown in FIG. 10, thescanned image shows the original documents A to C. Here, the originaldocuments A and B overlap. The original documents B and C overlap.

FIG. 11 shows an example of the contour line extracted by the processor11. As shown in FIG. 11, the processor 11 extracts a contour line 400.The contour line 400 is the contour lines of the original documents A, Band C.

FIG. 12 shows an example of vertices extracted by the processor 11. InFIG. 12, black dots indicate vertices. As shown in FIG. 12, theprocessor 11 extracts the vertices at the corners of the originaldocuments. The processor 11 extracts the vertex at a point where theedges of the overlapped original documents intersect.

FIG. 13 shows an example of the first and the second vertices extractedby the processor 11. In the example shown in FIG. 13, the processor 11extracts vertices 401 and 402. The vertex 401 and the vertex 402 aredirectly connected along the contour line 400.

The processor 11 has a function of searching for the third vertexforming the right angle with the first and the second vertices from theextracted vertices.

The processor 11 determines a third vertex such that a straight lineformed by the first vertex and the second vertex is orthogonal to astraight line formed by the second vertex and the third vertex.Alternatively, the processor 11 determines a third vertex such that thestraight line formed by the first vertex and the second vertex isorthogonal to a straight line formed by the first vertex and the thirdvertex.

FIG. 14 to FIG. 17 show an example of the operation in which theprocessor 11 searches for the third vertex.

In the example shown in FIG. 14, the processor 11 determines whether avertex 403 is the third vertex. As shown in FIG. 14, an angle formed bythe straight line formed by the vertex 401 and the vertex 402 and thestraight line formed by the vertex 402 and the vertex 403 is not a rightangle. The angle formed by the straight line formed by the vertex 401and the vertex 402 and the straight line formed by the vertex 401 andthe vertex 403 is not a right angle. Therefore, the processor 11determines that the vertex 403 is not the third vertex for the vertices401 and 402.

In the example shown in FIG. 15, the processor 11 determines whether avertex 404 is the third vertex. As shown in FIG. 15, an angle formed bythe straight line formed by the vertex 401 and the vertex 402 and astraight line formed by the vertex 402 and the vertex 404 is a rightangle. Therefore, the processor 11 determines the vertex 404 as thethird vertex for the vertices 401 and 402.

In the example shown in FIG. 16, the processor 11 determines whether avertex 405 is the third vertex. As shown in FIG. 16, an angle formed bythe straight line formed by the vertex 401 and the vertex 402 and astraight line formed by the vertex 402 and the vertex 405 is a rightangle. Therefore, the processor 11 determines that the vertex 405 is thethird vertex for the vertices 401 and 402.

In the example shown in FIG. 17, the processor 11 determines whether avertex 408 is the third vertex. Here, the processor 11 extracts vertices406 and 407 as the first and the second vertices.

As shown in FIG. 17, an angle formed by the straight line formed by thevertex 406 and the vertex 407 and the straight line formed by the vertex406 and the vertex 408 is slightly less than a right angle. It ispossible to extract the vertex 408 as the third vertex, as shown in FIG.17, because the processor 11 is configured to extract the third vertexeven if though the angle formed by the two lines is a little less orlarger than 90 degrees, e.g., in the range of 85 degrees to 95 degrees.

The processor 11 also has the function of estimating the fourth vertexwhich forms a rectangle with the extracted first and second vertices andthe searched third vertex.

In other words, the processor 11 estimates the fourth vertex such thatthe first to the fourth vertices form the rectangle. For example, theprocessor 11 calculates a vector extending from the second vertex to thethird vertex. The processor 11 estimates the fourth vertex by adding avector to the first vertex.

The method by which the processor 11 estimates the fourth vertex is notlimited to a specific method.

In the example shown in FIG. 15, the processor 11 estimates a vertex 411as the fourth vertex. As shown in FIG. 15, the vertices 401, 402, 404and 411 form the rectangle. In the example shown in FIG. 16, theprocessor 11 estimates a vertex 412 as the fourth vertex. As shown inFIG. 16, the vertices 401, 402, 405 and 412 form the rectangle.

In the example shown in FIG. 17, the processor 11 estimates a vertex 413as the fourth vertex. As shown in FIG. 17, the vertices 406 to 408 and413 form an approximate rectangle.

The processor 11 has a function of determining whether the rectangleformed by the first to the fourth vertices is within the document areadefined by the contour line.

The processor 11 sets a rectangle from the first to the fourth vertices.The processor 11 determines whether the set rectangle is inside thecontour line.

In the example shown in FIG. 15, the processor 11 sets a rectangle 421from the vertices 401, 402, 404 and 411. As shown in FIG. 15, theprocessor 11 determines that the rectangle 421 is within the documentarea. In the example shown in FIG. 16, the processor 11 sets therectangle 422 from the vertices 401, 402, 405, and 412. As shown in FIG.16, the processor 11 determines that the rectangle 422 is within thedocument area.

In the example shown in FIG. 17, the processor 11 sets a rectangle 423from the vertices 406, 407, 408 and 413. As shown in FIG. 17, theprocessor 11 determines that the rectangle 423 is outside the documentarea because it extends beyond the contour line.

The processor 11 stores the rectangles determined to be within thedocument area as the candidate rectangles in the RAM 13 or the NVM 14.

The processor 11 has the function of deleting the candidate rectanglecontained in another candidate rectangle.

The processor 11 acquires the candidate rectangle from the RAM 13 or theNVM 14. The processor 11 determines whether the candidate rectangle isincluded in another candidate rectangle. If the processor 11 determinesthat the candidate rectangle is included in another candidate rectangle,the processor 11 deletes the candidate rectangle.

For example, since the rectangle 421 is included in the rectangle 422,the processor 11 deletes the rectangle 421.

The processor 11 specifies the remaining candidate rectangle notincluded in another candidate rectangle as a single document area inwhich one original document appears.

FIG. 18 shows an example of the single document area specified by theprocessor 11. As shown in FIG. 18, the processor 11 specifies singledocument areas 431, 432 and 433.

The processor 11 has a function of calculating an overlap ratio of arange where the single document area overlaps with another singledocument area.

The processor 11 calculates the overlap ratio for each single documentarea. For example, the processor 11 determines an area of each singledocument area (“first area”) and then an overlapping area of one singledocument area with respect to another single document area (“secondarea”). Each area of the three document areas 431,432,433 is determinedbased on image data obtained by scanning, in particular the number ofpixels that are included in each respective document area. To determinethe overlapping area, pixel data of one document area (e.g., documentarea 431) is compared with pixel data of another document area (e.g.,document area 432) to determine the number of common pixels included inthe two areas, and the size of the overlapping area is calculated basedon the number of common pixels.

The processor 11 divides the second area by the first area to calculatethe overlap ratio of the single document area.

In the example shown in FIG. 18, the processor 11 specifies an area ofthe single document area 431. The processor 11 calculates an overlappingarea between the single document area 431 and the single document area432. The processor 11 calculates an overlap ratio of the single documentarea 431 by dividing the overlapping area by the area of the singledocument area 431.

The processor 11 specifies the area of the single document area 432. Theprocessor 11 calculates and sums the overlapping areas between thesingle document area 432 and the single document areas 431 and 433. Theprocessor 11 calculates the overlap ratio of the single document area432 by dividing the total overlapping area by the area of the singledocument area 432.

The processor 11 similarly calculates the overlap ratio for the singledocument area 433.

The processor 11 has a function of presenting a warning to the singledocument area of which the overlap ratio exceeds a predeterminedthreshold value.

For example, the processor 11 displays a warning for each singledocument area indicating that the overlap ratio exceeds thepredetermined threshold value on the display 21. For example, theprocessor 11 displays the document image in the single document areawith a warning.

FIG. 19 shows an example of the warning displayed on the display 21. Asshown in FIG. 19, the processor 11 displays the document image of theoriginal document A in the single document area 431, the document imageof the original document B in the single document area 432, and thedocument image of the original document C in the single document area433. The processor 11 controls to display thumbnails of the documentimages.

Here, the processor 11 determines that the overlap ratio of the singledocument area 431 and the single document area 432 exceeds apredetermined threshold value.

The processor 11 controls to display a warning in the vicinity of thedocument image of the original document A and the document image of theoriginal document B. Here, the processor 11 controls to display “ALERT!”as the warning. The processor 11 may control to display other phrase asthe warning. The processor 11 may change a color or a thickness of aframe of the document image.

As shown in FIG. 19, the processor 11 may control to display an icon 21a for deleting the document image (in particular, one of the documentimages A, B, and C selected by the user), an icon 21 b for canceling thescanning operation, and an icon 21 c for saving the document image.

The processor 11 has a function of generating the files individuallyincluding the respective document images.

If a tap on the icon 21 c is received, the processor 11 generates thefiles including the respective document images individually.

For example, the processor 11 generates a file including the documentimage of the original document A, a file including the document image ofthe original document B, and a file including the document image of theoriginal document C.

The processor 11 may store the generated file in the NVM 14. Theprocessor 11 may store the file in a memory (such as a USB memory)inserted in the image processing apparatus 10. The processor 11 maytransmit the file to the external device through the communicationinterface 15.

Next, an example of the operation of the image processing apparatus 10is described. FIG. 20 and FIG. 21 are flowcharts of the operation of theimage processing apparatus 10. Here, the user sets the original documentin the scanner 17 and inputs an operation to start the scan to theoperation panel 19.

First, the processor 11 of the image processing apparatus 10 acquiresthe scanned image obtained by scanning the original document from thescanner 17 through the scanner interface 16 (ACT 41). Once the scannedimage has been acquired, the processor 11 executes the binarizationprocessing on the scanned image (ACT 42).

Once the binarization process has been executed, the processor 11extracts the contour line of the document area from the scanned image(ACT 43). Once the contour line has been extracted, the processor 11extracts the vertices from the contour line (ACT 44).

Once the vertices have been extracted, the processor 11 determineswhether the number of the vertices in one contour line is five or more(ACT 45). If it is determined that the number of vertices in one contourline is five or more (Yes in ACT 45), the processor 11 executes theimage separation processing (ACT 46).

If it is determined that the number of the vertices in one contour lineis not five or more (No in ACT 45), or once the image separation processhas been executed (ACT 46), the processor 11 extracts one document imagefrom the scanned image (ACT 47).

Once the document image has been extracted, the processor 11 correctsthe inclination of the document image (ACT 48). Once the inclination ofthe document image has been corrected, the processor 11 determineswhether there is another single document area (ACT 49).

If it is determined that there is another single document area (Yes inACT 49), the processor 11 returns to the processing in ACT 47.

If it is determined that there is no other single document area (No inACT 49), the processor 11 determines whether there is another contourline (ACT 50).

If it is determined that there is another contour line (Yes in ACT 50),the processor 11 returns to the processing in ACT 45. If it isdetermined that there is no other contour line (No in ACT 50), theprocessor 11 causes the extracted thumbnail of the document image on theto be displayed on display 21 (ACT 51).

Once the thumbnail has been displayed, the processor 11 determineswhether the overlap ratio corresponding to the document image exceedsthe predetermined threshold value (ACT 52). If it is determined that theoverlap ratio exceeds the predetermined threshold value (Yes in ACT 52),the processor 11 causes the warning to be displayed (ACT 53).

If it is determined that the overlap ratio is less than thepredetermined threshold value (No in ACT 52) or once the warning hasbeen displayed (ACT 53), the processor 11 determines whether theoperation for storing the document image is received through theoperation panel 19 (ACT 54).

If it is determined that the operation for storing the document image isnot received (No in ACT 54), the processor 11 repeats the processing inACT 54.

If it is determined that the operation for storing the document image isreceived (Yes in ACT 54), the processor 11 stores the document image ina predetermined memory (ACT 55). Once the document image has been storedin the predetermined memory, the processor 11 ends the operation.

Next, an example of the operation in which the processor 11 executes theimage separation processing (ACT 46) is described. FIG. 22 is aflowchart of the operation in which the processor 11 executes the imageseparation processing.

The processor 11 extracts adjacent first and second vertices from theextracted vertices (ACT 61). Once the first and the second vertices havebeen extracted, the processor 11 searches for the third vertex formingthe right angle with the first and the second vertices (ACT 62).

Once the third vertex has been searched, the processor 11 estimates thefourth vertex forming a rectangle with the first to the third vertices(ACT 63).

Once the fourth vertex has been estimated, the processor 11 forms therectangle from the first to the fourth vertices (ACT 64). Once therectangle has been formed, the processor 11 determines whether theformed rectangle is inside the contour line (ACT 65).

If it is determined that the formed rectangle is inside the contour line(Yes in ACT 65), the processor 11 stores the rectangle as the candidaterectangle (ACT 66).

If it is determined that the formed rectangle is not inside the contourline (No in ACT 65), or once the rectangle has been stored as thecandidate rectangle (ACT 66), the processor 11 determines whether thereis another third vertex that forms the right angle with the first andthe second vertices (ACT 67).

If it is determined that there is another third vertex (Yes in ACT 67),the processor 11 returns to the processing in ACT 62.

If it is determined that there is no other third vertex (No in ACT 67),the processor 11 determines whether there are other adjacent first andsecond vertices (ACT 68). If it is determined that there are otheradjacent first and second vertices (Yes in ACT 68), the processor 11returns to the processing in ACT 61.

If it is determined that there are no other adjacent first and secondvertices (No in ACT 68), the processor 11 deletes the candidaterectangle contained in another candidate rectangle (ACT 69). Once thecandidate rectangle contained in another candidate rectangle has beendeleted, the processor 11 specifies the remaining candidate rectangle asthe single document area (ACT 70).

If the remaining candidate rectangle is specified as the single documentarea, the processor 11 calculates the overlap ratio of each singledocument area (ACT 71). After the overlap ratio of each single documentarea is calculated, the processor 11 ends the operation.

The processor 11 may transmit the document image to the external device.The processor 11 may receive the selection of the document image to bestored and store the selected document image.

In other embodiments, the processor 11 may extract the document image ofeach original document based on the scanned image in which four or moreoverlapping original documents appear.

The processor 11 may generate one file containing the document images ofthe respective original documents arranged in the overlapped manner. Forexample, the processor 11 may generate one file from the document imagesof the original documents A to C.

The image processing apparatus as described above extracts the thirdvertex forming the right angle from the adjacent first and secondvertices. The image processing apparatus estimates the fourth vertexforming the rectangle with the first to the third vertices. The imageprocessing apparatus extracts the document image from the scanned imagebased on the rectangle.

As a result, the image processing apparatus can also extract thedocument image for an original document (where the original documentoverlaps with a plurality of the original documents) of which the threecorners are not consecutive on the contour line. Therefore, the imageprocessing apparatus can specify the document image of each originaldocument even if three or more original documents overlap.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the invention. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinvention. The accompanying claims and their equivalents are intended tocover such forms or modifications as would fall within the scope andspirit of the invention.

What is claimed is:
 1. An image processing apparatus, comprising: aprocessor configured to: extract a first outermost contour line of afirst document area in image data of a plurality of documents, the firstdocument area including a first document and a second document, thefirst document and the second document partially overlapping each other,extract a second outermost contour line of a second document area in theimage data, the second document area including a third document and afourth document, the third document and the fourth document partiallyoverlapping each other, the first document area and the second documentarea not overlapping with each other in the image data, extract verticesof the first outermost contour line, extract document image data of thefirst document and the second document in the first document area basedon the extracted vertices of the first outermost contour line, calculatean amount of overlap between the first and second documents in the firstdocument area, generate a warning message if the calculated amount ofoverlap between the first and second documents is greater than athreshold amount, generate a first single file including the extracteddocument image data for the first document and the second document,extract vertices of the second outermost contour line, extract documentimage data of the third document and the fourth document in the seconddocument area based on the extracted vertices of the second outermostcontour line, and generate a second single file including the extracteddocument image data for the third document and the fourth document; anda memory configured to store the first single file and the second singlefile.
 2. The image processing apparatus according to claim 1, whereinthe image data is loaded from the memory.
 3. The image processingapparatus according to claim 1, wherein the processor is furtherconfigured to correct an inclination of the extracted document imagedata.
 4. The image processing apparatus according to claim 1, whereinthe processor is configured to: extract first to third vertices of thefirst outermost contour line that are adjacent to one another and form aright angle or an approximate right angle, estimate a fourth vertex fromthe first to third vertices such that the first to fourth vertices forma rectangle or an approximate rectangle, and extract document image datafrom the image data based on the rectangle or the approximate rectangle.5. The image processing apparatus according to claim 4, wherein theprocessor is configured to determine whether the rectangle is formedwithin the document area and extract the document image data from theimage data only if the rectangle is inside the document area.
 6. Theimage processing apparatus according to claim 1, wherein the processoris configured to: acquire the image data from the memory; and perform abinarization process on the image data before extracting the firstoutermost contour line.
 7. A method of processing image data including aplurality of documents, the method comprising: extracting a firstoutermost contour line of a first document area in image data of aplurality of documents, the first document area including a firstdocument and a second document, the first document and the seconddocument partially overlapping each other; extracting a second outermostcontour line of a second document area in the image data, the seconddocument area including a third document and a fourth document, thethird document and the fourth document partially overlapping each other,the first document area and the second document area not overlappingwith each other in the image data; extracting vertices of the firstoutermost contour line; extracting document image data of the firstdocument and the second document in the first document area based on theextracted vertices of the first outermost contour line; calculating anamount of overlap for the first document and the second document in thefirst document area, generating a warning message if the calculatedamount of overlap for the first and second documents is greater than athreshold amount, generating a first single file including the extracteddocument image data for the first document and the second document;extracting vertices of the second outermost contour line; extractingdocument image data of the third document and the fourth document in thesecond document area based on the extracted vertices of the secondoutermost contour line; generating a second single file including theextracted document image data for the third document and the fourthdocument; and storing the first single file and the second single filein a memory.
 8. The method according to claim 7, further comprising:loading the image data from the memory.
 9. The method according to claim7, further comprising: correcting an inclination of the extracteddocument image data.
 10. The method according to claim 7, furthercomprising: extracting first to third vertices of the first outermostcontour line that are adjacent to one another and form a right angle oran approximate right angle; estimating a fourth vertex from the first tothird vertices such that the first to fourth vertices form a rectangleor an approximate rectangle; and extracting document image data from theimage data based on the rectangle or the approximate rectangle.
 11. Themethod according to claim 10, further comprising: determining whetherthe rectangle is formed within the document area and extracting thedocument image data from the image data only if the rectangle is insidethe document area.
 12. The method according to claim 7, furthercomprising: acquiring the image data from the memory; and performing abinarization process on the image data before extracting the firstoutermost contour line.
 13. A non-transitory computer readable mediumcomprising instructions that are executable in an image processingapparatus, wherein the instructions when executed in the imageprocessing apparatus cause the image processing apparatus to carry out amethod of processing image data, said method comprising: extracting afirst outermost contour line of a first document area in image data of aplurality of documents, the first document area including a firstdocument and a second document, the first document and the seconddocument partially overlapping each other; extracting a second outermostcontour line of a second document area in the image data, the seconddocument area including a third document and a fourth document, thethird document and the fourth document partially overlapping each other,the first document area and the second document area not overlappingwith each other in the image data; extracting vertices of the firstoutermost contour line; extracting document image data of the firstdocument and the second document in the first document area based on theextracted vertices of the first outermost contour line; calculating anamount of overlap for the first document and the second document in thefirst document area, generating a warning message if the calculatedamount of overlap for the first and second documents is greater than athreshold amount, generating a first single file including the extracteddocument image data for the first document and the second document;extracting vertices of the second outermost contour line; extractingdocument image data of a third document and a fourth document in thesecond document area based on the extracted vertices of the secondoutermost contour line; generating a second single file including theextracted document image data for the third document and the fourthdocument; and storing the first single file and the second single filein a memory.
 14. The non-transitory computer readable medium accordingto claim 13, wherein the method further comprises: acquiring the imagedata from the memory; and performing a binarization process on the imagedata before extracting the first outermost contour line.
 15. Thenon-transitory computer readable medium according to claim 13, whereinthe method further comprises: calculating an amount of overlap for thethird document and the fourth document in the second document area; andgenerating a warning message if the amount of overlap for the third andfourth documents is greater than the threshold amount.
 16. The imageprocessing apparatus according to claim 1, wherein the processor isfurther configured to: calculate an amount of overlap between the thirdand fourth documents in the second document area, and generate a warningmessage if the calculated amount of overlap between the third and fourthdocuments is greater than the threshold amount.
 17. The method accordingto claim 7, further comprising: calculating an amount of overlap for thethird document and the fourth document in the second document area; andgenerating a warning message if the amount of overlap for the third andfourth documents is greater than the threshold amount.